Security and resilience of Automated Teller Machines (ATMs—one type of a Self-Service Terminal) to attacks and common issues can lead to breaches in the security integrity of: the ATMs, the network, and user account information. Nefarious individuals and even well-funded and equipped state actors are continuously trying to breach and attack ATMs, users' account information, and financial systems interfaced to the ATMs.
Moreover, when an ATM is offline, the ATM is unavailable for customer transactions. This results in lost revenues for the financial institutions and companies that provide the ATMs. Much worse, is that a customer is unlikely to return to an ATM if that ATM is offline more than a few times when the customer is in need of the ATM. ATMs often experiences glitches where the state of the ATM can become corrupt resulting in failures that can sometimes be fixed with a simple reboot of the ATM, or which may be more serious and require a technician to properly resolve.
Also, when ATM hardware and/or software resources are patched or upgraded, the discovery of a corrupted or malfunctioning hardware and/or software resource may not be immediately discoverable and may only surface after some unexpected resources are processed in a predefined order after the changes are made to the ATM. In fact, the ATM failures may appear to have no real correlation that can be detected by technicians. When more than a few failures occur in this scenario, the ATM changes are usually backed out to prevent future failures, even when the changes were recommended by a hardware and software vendor for security or for proper vendor support.
Suffice it to say, the security and high-availability of ATMs are of utmost significance to the financial industry. However, because ATMs are processing devices and state-based machines, their memories, storages, configuration settings, and resources can, over time, be corrupted and not function properly or as intended, resulting in ATM unavailability for customer transactions and potentially exposing the ATM to security breaches.